Variable speed drive means for printing of short texts in rotary printing machines



Dec. 22, 1953 J CHAMBQN 2,663,256

VARIABLE SPEED'DR'IVE MEANS FOR PRINTING 0F SHORT TEXTS IN ROTARY PRINTING MACHINES Filed May 15, 1951 3 Sheets-Sheet 1 Dec. 22, 1953 L .1. CHAMBON VARIABLE SPEE 2,663,256 D DRIVE MEANS FOR PRINTING OF IN ROTARY PRINTING MACHINES SHORT TEXTS 5 Sheets-Sheet 2 Filed May 15, 1951 Dec. 22, 1953 Filed May 15, 1951 CHAMBON 2,663,256

L. J. VARIABLE SPEED DRIVE MEANS FOR PRINTING OF SHORT TEXTS IN ROTARY PRINTING MACHINES 3 Sheets-Sheet 3 MW Viv/V 4w Patented Dec. 22, 1953 VARIABLE SPEED DRIVE MEANS FOR PRINT- IN G OF SHORT TEXTS IN ROTARY PRINT- ING MACHINE S Louis Iean Chambon, Paris, France, assignor to Society Machines Chambon, Paris, France Application May 15, 1951, Serial No. 226,429

Claims priority, application France August 26, 1946 7 Claims.

The present application is a continuation-inpart of application Serial No. 763,208, filed July 24, 1947, now abandoned.

The present invention concerns methods and apparatus for the printing of short texts wherein the peripheral distance separating two successive texts carried by the printing cylinder is different from the distance separating the printings of said texts on the band to be printed.

To obtain a good printing, it is necessary, at the time when the text is in contact with the band, that the speed of peripheral displacement of the text be substantially equal to that of the band. It is necessary, therefore, to give the printing cylinder variable speeds.

Until now, it was estimated that the speeds of the band and of the text should be strictly identical for the whole duration of the printing. Machines known at present, therefore, in order to meet this condition, comprise sets of cams which have to be replaced by others, according to cases, after stopping the machine, or complicated devices.

The applicant found that for the printing of short texts, of small lengths in the longitudinal direction of the band, a good printing could be obtained if the peripheral speed of the text was slightly different from that of the band.

According to a first feature of the present invention, the displacement speed of the text to be printed is variable during the whole duration of the printing and is equal to that of the band to be printed during an instant only of this duration of the printing.

In a first type of embodiment, the displacement speed of the text, except during said instant, is always higher than that of the band.

In a second type of embodiment, the displacement speed of the text, except during said instant, is always lower than that of the band.

In both types of embodiment, the differences between the displacement speeds of the text and the band for the duration of the printing are, of course, very low.

According to a second feature of the invention, the printing cylinder is given such a rotation that the angle A, covered by said cylinder from the zero instant to instant t, is given by the following formula:

wherein Cot is proportional to the speed of displacement of the band and D is a variable parameter.

Other features of the present invention will appear from the following description of a particular embodiment of the present invention, given merely by way of example.

Figure 1 is an assembly view of a machine according to the present invention.

Figure 2 is a section along line 11-11 of Figure 1.

Figure 3 is an end view of the portion of the machine shown on Figure 2.

Figure 4 is a diagram showing the law of angular displacements of the mechanism described.

I is the general shaft of the machine, which controls, through sets of helical wheels 2 and 3, either the shafts 3| of the cylinders 32 driving a paper band 19, or a shaft 4. The shafts 3| and 4 are supported on the frame 5 of the machine. On the overhung portion of the shaft 4 is keyed a crank arm 6. The axle of the arm I of this crank is off center with respect to the axis of the shaft 4 by a length 0. On this arm 1 a pinion 8, toothed on the outside, and having a radius r, is mounted free, and an arm 9 is secured thereto, This arm 9 offers an elongated window In, the axis of which is parallel to that of the arm and intersects the axis of the arm 1. Through this window passes the end of a stud I l, which may be displaced inside a window [2, of a part l3. The latter is mounted free about the shaft 4, but is immobilized by two shafts l4 carried by the frame 5 of the machine, placed on both sides of the shaft 4 and passing through holes drilled in the side extensions l5 of the part 13. The axis of the window l2 intersects the axis of the shaft 4. The stud II, the axis of which is parallel with that of the shaft 4, is carried by a slide l6, acting as a nut on a threaded rod ll, which can rotate about its axis under the action of the handwheel l8, but cannot be displaced parallel to its axis. Under such conditions, the rotation of the handwheel causes a displacement of the stud in the window l2. The distance between the axis of the stud II and the axis of the shaft 4 will be designated by d.

On the axis of the shaft 4 is another shaft I9, carried by the frame 5 of the machine. On one of the ends of said shaft I9 is keyed a cup 20, offering, inside, a set of teeth 2! which gear with the pinion 8 and the radius of which is R=r+e. This shaft I9 carries a printing cylinder 22, which, in the present case, carries three texts 23, equally spaced on the periphery. V

Parallel with this shaft, 19, a shaft 24 is arranged, on which is keyed a counter-part cylinder 25. The shaft 24 is driven by the shaft is through the gears 26, 21.

It can be shown that, calling A the angle moved by the shaft [9, v, the angular velocity of the shaft 4 and t'the'time,

The second term of this equation becomes zero tarr for vt=lc1r wherein 7c is aninteger andthe. value ofAis The derivative A of A with respect to t is R- r d cos vt- (Rr)' It will be seen that A for utzlcvr' which means: that: the curve: oirers. points of inflexien for vt=k1r If k is zero or. an even number,

The speed of therband. b is equal to pot (n being a constant). The proportionality coeflicient p is determined once for all so that. the peripheral speed of the cylinders 32. (this speed is. constant and equal to the displacement speed of the. band b) is equal to the. displacement speed of the. texts 23 for vt==lc1r (the values of 76. being either even or odd). This proportionality coefficient 11 depends on the number n of texts 23 carriedby the cylinder 22. The number n, in fact, is equal. to

The foregoing formulae are derived in the following manner:

In order to demonstrate that if A is the angle passed through by shaft 19' which is integral with cup then i) is the angular speed of shaft 4 and t is the time, one may write:

r r (R-1')sinvt A vt(1 R R d-(Rr) cos vt Figure 4 shows schematically Figure 3 of the drawings. On this figure:

o is the center of the shaft 4,

P is the center of the gear 8,

C is the center of stud H (a point fixed for a particular regulation),

I is a fixed point of origin on gear 8.

d is the angle of rotation of shaft 4,

6 is the angle OCP: the angle between the axis of arm 9 and that of part 13 (these angles will be expressed in radians).

It is convenient:

e designates the distance OP, 1' the radius PB,

R the radius OB,

d the distance 00.

Examination of the figure shows that:

4 Point I has a relative movement with respect to the circle of center 0 and of radius OB, the trajectory of which is a hypocycloid arc since the gear 3 rolls without sliding on the cup 28 form" ing. an: internal; gear. I has moreover a rotary movement about 0 due to the rotation of cup 20 and angle A.

At time 0 (zero) the point cl, 1', I are confused. Therefore:

'lihe: figure shows that:

BB'=BI+IB' or- BI=BBBI [ll Expressing the arcs as functions of the radii and. of. the angles,

B1=r.(d+ 6) Equation Elli can be written:

R.=R.dr(dX).

3 It follows:

I. 1 1ld 1 R e) 2 In the following; the angle 3 as a function of the angle (2 is calculated. For this purpose,

project the point C onto 013 at H and the equation is written:

QH=OP+PH OP==QH-PH [3:]

wherein:

OP=e

OH=OC cos d=d cos d PH=PC cos (12+ 0) To calculate PC: In triangle OPC: the sides are proportional to the sines of the opposite angles,

so that:

Simplifying by- '(cos d) ii e cos d=e 1' 4* acme 4 R) R are 1-0 cos 6 By replacing e and d by the valuesabove, calculated e=Rt (1:01? It is foundz v I T r I R'R sin at R) R 1 me As may be seen in Fig. 4, if OB is the curve of the spaces of the strip I, the angle tOV characterizes the velocity of the strip I.' In any point M of the curve C of the spaces of the cylinder 22, theperipheral instantaneous velocity is dependent upon the inclination of the tangent MT. Thus the ratio of the transmission I connecting the shaft 4 to the shaft I9 is Rr 'r cote (R-r) sin at R Rvt d( Rr) cos vi In order that the peripheral velocity of the cylinder 22 be equal to the rate of displacementof the 5 strip 6, it is only necessary that the tangent to the curvev C be parallel to the straight lineQOV. This is the case for the point I. In order thatthe difference in the velocities of the cylinder 22 and of the strip b be as reduced as possible during the printing period, provision will be'made in order that the point I be placed at a point of inflection of the curve C.

It should be noted that the speed of the text 23 at the points of infiexion corresponding to the printings is given by the value of A and should be equal to the velocity of the band I). The dimensions R, r, V and the proportionality coefiicient p are constructional constants, and only 11 can vary. To ensure the identity between the speed of the text 23 at the points of inflexion of the formula A corresponding to printings and that of the band b, it will be sufficient to modify the value of d, which may be effected by simply operating the wheel l8, and this without stopping the machine.

I claim: 1. Process for printing short texts on a band moving at a constant speed, wherein the printing cylinder carrying at least one text is actuated by a movement, the rotational speed of which is given by the following formula:

' 6' sin vt 8J0 igjTt wherein C is a constant determined by the dimen- 6 der bearing "the inscriptions to be printed and means'for' giving said printing cylinder a variable speed of rotation, said means consisting of a drive shaft of constant speed of rotation, a driven shaft coaxial withsaid drive shaft driving the printing cylinder, a first externally toothed pinion whose axis of rotation is parallel and ofiset in relation to that of the driving and driven shafts and which is driven by the drive shaft, a second internally toothed pinion meshing with said first pinion c0- axial with the driven shaft and driving the latter, the radius of this second pinion being equal to the sum of the radius of the first pinion and. the

. e'ccentricityof the latter in'relation to the axis of the driving and driven shafts, a rectilinear guide integral with the first pinion," an element capable of moving in said guide, and meansfor displacing'and immobilizing said element on a fixed path.

3. A rotary machine for printing inscriptions of: small width on a'strip to be printed moving at constant speed, having at least one printing cylinderbearing the inscriptions to be printed and means for giving said printing cylinder a variable speed of rotation, said means consisting of a drive shaft of constant speed of rotation, a driven shaft coaxial with said drive shaft driving the printing cylinder, an eccentric crankpin supported by the drive shaft, a first externally toothed pinion mounted loose on said crankpin, a second internally toothed pinion meshing with said first pinion coaxial with the driven shaft and driving the latter, the radius of this second pinion being equal to the sum of the radius of the first pinion and the eccentricity of said crankpin in relation to the drive shaft, a rectilinear guide integral with the first pinion, an'element capable of moving in said guide, and means for displacing and immobilizing said element on a fixed path,

' 4. A rotary machine for printing inscriptions of small width on a strip to be printed moving at constant speed, having at least one printing cylinder bearing the inscriptions to be printed and means for giving to said printing cylinder a variable speed of rotation, said means consisting of a drive shaft of constant speed of rotation, a driven shaft coaxial with said drive shaft driving the printing cylinder, an eccentric crankpin supported by the drive shaft, first externally toothed pinion mounted loose on said crankpin, a, second internally toothed pinion meshing with said first pinion coaxial with the driven shaft and driving the latter, the radius of this second pinion being equal to the sum of the radius of the first pinion and the eccentricity of said crankpin in relation to the drive shaft, an arm integral with the first pinion, a window provided in said arm and extending along a straight line passing through the axis of rotation of said first pinion, an element passing through said window, means for displacing said element along a straight line intersecting the common axis of the driving and driven shafts, and means for immobilizing said element on this latter line.

5. A rotary machine for printing inscriptions of small width on a strip to be printed moving at constant speed, havingat least one printing cylinder bearing the inscriptions to be printed and means for giving said printing cylinder a variable speed of rotation, said means consisting of a drive shaft of constant speed of rotation, a driven shaft coaxial with said drive shaft driving the printing cylinder, an eccentric crankpin supported by the drive shaft, a first externally toothed pinion mounted loose on said crankpin, a

second internally toothed pinion meshing with said first pin and coaxial with the driven shaft and driving the latter, the radius of this second pinion being equal to the sum or the radius of the first pinion and the eccentricity of said crankpin in relation to the driving shaft, an arm integral with the first pinion, window provided in said arm, and extending along a straight line passing through the axis of rotation of said first pinion, an element passing through said window, a fixed frame, a threaded bar supported by said fixed frame and capable of rotating about its axis and unable to shift along its axis, a, nut coopcrating with said threaded bar and integral with said element, and means for rotating said threaded bar.

6. In a rotary printing machine, a printing cylinder, means for displacing a band to be printed at a constant speed, means for imparting to said printing :cylinder a variable rotation speed, a driving shaft rotating with .an angular speed 12, a driven shaft on which is attached the printing cylinder and. a transmission, driven by the driving shaft, driving the driven shaft and having a ratio-T given by the formula:

said transmission comprising a crank of radius R-r driven by the driving shaft, a first outer toothed pinion, having a radius 1* which is mounted free on the crank arm of said crank, a second inner toothed pinion having a radius R and meshing with said first pinion, alever operatively associated with said first pinion comprising a window which extends parallel to a straight line passing through the axis of said first pinion, a stud passing through said window in said lever, means for displacing said stud along a line passing through the common axis of the driving and 8, driven shafts and means for locking said stud at a distanc d from said axis.

7. In a rotary printing machine comprising a printing cylinder bearing n inscriptions to be printed, means for displacing the strip being printed at a constant speed, means for imparting to said printing cylinder 9, variable rotation speed comprising a driving shaft having an angular speed a, a driven shaft to'which is attached the printing cylinder, a transmission which is driven by the driving shaft and which drives the driven shaft, said transmission characterized with relation to the angular speed 11 andwith relation to the number of strips n in accordance with the following equation:

1 not tang d wherein R and r are determined by the formula t is the time and d is a variable, controlled by the operator and adjusted to make the speed of the inscription equal to the speed of the strip at the moment when the strip and inscription make contact.

--cos vi LOUIS JEAN CHAMBON. 

